Occurrence of aflatoxin M1 in traditional cheese consumed in Esfahan, Iran

Aflatoxin M-1 (AFM(1)) was determined by enzyme linked immunosorbent assay in 88 samples of traditional cheese consumed in Esfahan city of Iran. In 47 of 88 samples (53.4%), the presence of AFM(1) was detected in concentrations between 82 ng/kg and 1254 ng/kg. The mean level of AFM(1) of positive samples was 412 ng/kg. AFM(1) in 28 (31.8%) samples was higher than the maximum tolerance limit (250 ng/kg) accepted by some countries. Statistical analysis showed that there were no significant differences (P>0.05) between the mean concentrations of AFM(1) in cheese samples of spring, summer, autumn and winter. However, the mean concentration of AFM(1) in cheese samples from spring and summer was significantly lower than autumn and winter (P=0.05). It can be concluded that the high occurrence of AFM(1) in cheese is probably due to the presence of aflatoxin in the feed and cheese milk. This condition should be considered as a probable hazard for human health.